1. Field of the Invention
The present invention relates to an image recording apparatus and, in particular, to a construction of a frame assembly as a supporting apparatus.
2. Discussion of Related Art
FIG. 13 illustratively shows an image recording portion of a conventional ink-jet recording device. The conventional ink-jet recording device includes a platen 1 on which a recording sheet is placed; and an ink-jet recording head 2 that is reciprocated, along the platen 1, in a main scanning direction (i.e., a direction perpendicular to the drawing of FIG. 13) while ejecting droplets of ink toward the recording sheet so as to record a desired image thereon. Therefore, recording a clear image needs to position accurately the platen 1 and the recording head 2 relative to each other and maintain the accurate relative-positional relationship between the two elements 1, 2 during an image recording operation. To this end, the conventional ink-jet recording device employs a frame assembly 3 as a supporting device that supports the platen 1 and the recording head 2.
The frame assembly 3 includes a main frame 4, and two slide-base members 5, 6 that are supported by the main frame 4. The main frame 4 has a generally U-shaped transverse cross section, and extends in the direction perpendicular to the drawing of FIG. 13. The main frame 4 is provided with two crossing members 7 that cooperate with each other to increase a rigidity of the main frame 4. The platen 1 is fixed to the main frame 4. One slide-base member 5 is fixed to respective one end portions of the two crossing members 7; and the other slide-base member 6 is fixed to the respective other end portions of the two crossing members 7. Each of the two slide-base members 5, 6 also has a generally U-shaped transverse cross section. The recording head 2 bridges the two slide-base members 5, 6 such that the head 2 is movable in the direction perpendicular to the drawing of FIG. 13.
To position accurately the recording head 2 relative to the platen 1 when the head 2 is moved along the platen 1, it is needed to fix accurately the two slide-base members 5, 6 to the main frame 4. To this end, in a conventional method, the frame assembly 3 is assembled such that the two slide-base members 5, 6 are accurately positioned relative to the main frame 4, before the platen 1 and the recording head 2 are assembled with the frame assembly 3. More specifically explained, in the conventional method, the main frame 4 is provided with one or more engaging portions, and each of the two slide-base members 5, 6 is provided with one or more engageable portions. In a state in which the engaging and engageable portions are engaged with each other, the engaging portions are caulked to position accurately the two slide-base members 5, 6 relative to the main frame 4. The image recording portion is assembled in such a manner that the platen 1 and the recording head 2 are assembled with the pre-assembled frame assembly 3.